The present invention relates to a mass spectroscope for detecting an analyte.
Among mass spectroscopy methods used for the identification of an analyte or other like purposes is a mass spectrometry whereby an analyte is irradiated by laser light to ionize and desorb the analyte, and the desorbed analyte is detected according to mass.
Among the methods of ionizing an analyte used in the mass spectroscopy are, for example, the MALDI (matrix-assisted laser desorption/ionization) method and the SALDI (surface-assisted laser desorption/ionization) method, as described in “Analytical Chemistry,” Volume 77, Number 16, pp. 5364 to 5369.
The MALDI method is a method whereby a sample prepared by mixing an analyte into a matrix (e.g., sinapic acid or glycerin) is irradiated by light to allow the matrix to absorb the energy of the light with which the sample was irradiated, the analyte is vaporized together with the matrix, and the proton transfer is allowed to take place between the matrix and the analyte, achieving ionization of the analyte.
The SALDI method is a method whereby no matrix is used and the surface of a substrate upon which a sample is placed is instead given functions similar to those of a matrix so that the analyte is ionized directly upon the surface of the substrate. Analytical Chemistry referred to above describes a DIOS method wherein the substrate is a porous silicon plate having pores each measuring hundreds of nanometers.
JP 2007-171003 A describes a mass spectroscope using a mass analysis substrate wherein at least part of the surface upon which an analyte is placed (i.e., detection surface) is adapted to be a rough metallic surface capable of exciting localized plasmons upon irradiation with laser light. That mass spectroscope detects the mass of an analyte by irradiating the detection surface of the mass analysis substrate with laser light to desorb the analyte from the detection surface and trap the analyte desorbed from the detection surface.
Mass spectroscopes are required to be capable of a high-accuracy mass detection of an analyte and an efficient ionization thereof with less energy.